The present application relates to a semiconductor structure and a method of forming the same. More particularly, the present application relates to a semiconductor structure including a functional gate structure straddling a silicon germanium alloy fin, wherein high quality source/drain structures are formed by epitaxy on opposite sides of the functional gate structure.
For more than three decades, the continued miniaturization of metal oxide semiconductor field effect transistors (MOSFETs) has driven the worldwide semiconductor industry. Various showstoppers to continued scaling have been predicated for decades, but a history of innovation has sustained Moore's Law in spite of many challenges. However, there are growing signs today that metal oxide semiconductor transistors are beginning to reach their traditional scaling limits. Since it has become increasingly difficult to improve MOSFETs and therefore complementary metal oxide semiconductor (CMOS) performance through continued scaling, further methods for improving performance in addition to scaling have become critical.
The use of non-planar semiconductor devices such as, for example, semiconductor fin field effect transistors (FinFETs) is the next step in the evolution of complementary metal oxide semiconductor (CMOS) devices. Semiconductor fin field effect transistors (FETs) can achieve higher drive currents with increasingly smaller dimensions as compared to conventional planar FETs. In order to extend these devices for multiple technology nodes, there is a need to boost the performance with high-mobility channels.
A silicon germanium alloy (i.e., SiGe) is one promising channel material that can be used as a semiconductor fin of FinFET devices because of its high-carrier mobility. The epitaxial growth of source/drain structures around such SiGe fins is very challenging due to growth on a damaged sidewall surface of the SiGe fins. As such, there is a need for providing a method in which high quality source/drain structures can be formed around SiGe fins.